The invention relates to a tensioning device for maintaining two splined shaft sections in engagement without play in the direction of rotation.
A tensioning device of this type is known from German patent (DE-PS) No. 1,808,076. It serves to maintain the splined shaft profiles virtually without play while maintaining an axial mobility.
In this case the tensioning member forms a comparatively wide cylindrical ring made of resilient plastic which is to be fitted onto the shaft section to be inserted in the hublike shaft section, and which adjoins the end face of the hublike shaft section.
The tensioning element is constructed as a cylindrical collet, which is screwable by a female screwthread threaded onto an end male screwthread of the hublike shaft section. This collet, which is drawn radially inwards at its collet end remote from the hublike shaft section in order to brace a bracing ring which it receives, houses the resilient ring.
When the collet is screwed onto the hublike shaft section, the ring becomes tensioned under compression between the bracing ring and the end face of the hublike shaft section. This has the result that the plastic of the ring is pressed into the splined shaft profile of the shaft section which houses the ring, both against the end face of the hublike shaft section and against the inside face of the collet.
The ring therefore produces the desired freedom from play in the direction of rotation between the two shaft sections of their splined shaft profiles.
This device is therefore composed of a total of three components, each requiring separate manufacture, which have to be fitted onto one of the two shaft sections before the latter are plugged together. Then, after the splined shaft profiles are mutually engaged, the collet has to be screwed additionally onto the male screwthread of the hublike shaft section in order to compress the ring.
An underlying object of the invention is to disclose a tensioning device for maintaining in engagement without play in the direction of rotation the splined shaft profiles of two mutually longitudinally slidable shaft sections, for which production and assembly are considerably simplified and with which a special manual actuation of the tensioning member can be eliminated.
This object is achieved according to the invention by providing an arrangement wherein the hublike shaft section is slitted tongs fashion at its free end region, wherein the tensioning member is at least one slightly tapered annular spring arranged on the slitted end region of the hublike shaft section, and wherein the tensioning element is a stop against which the annular spring is pressable by its outer edge part in the course of bringing the two shaft sections into mutual engagement in order to generate a radial tensioning force.
The tensioning device according to the invention therefore comprises only two device parts to be associated separately with the two shaft sections, namely the annular spring and the stop, the annular spring being available as an easily assembled standard part. The annular spring and the hublike shaft section which houses it must then be mutually coordinated in diameter so that, at least when the radial stretched position of the annular spring is reached, or when the annular spring is pressed flat, the desired playfree engagement of the splined shaft profiles is obtained with simultaneously a slight axial sliding mobility.
Independently of the axial stroke of the hublike shaft section required to tension the annular spring, its conformation and thickness influence the axial and radial forces which it can generate.
At least one customary plate spring or annular tension washer, or a combination of corresponding plate springs and/or annular tension washers, may advantageously be used as an annular spring according to certain preferred embodiments of the invention.
Such annular springs, in the relaxed state, can be fitted without difficulty onto the hublike shaft section with a correspondingly enlarged inside diameter. The axially directed return force residual in such annular springs in their radial stretched position efficaciously assists the corresponding dismantling operations when the annular springs are relaxed in order to release the two shaft sections.
The annular spring will then conveniently be brought into engagement with a circumferential groove provided at the slitted end region of the hublike shaft section, which groove simultaneously forms a keeper device for the annular spring, so that the latter can be preassembled on the shaft section.
The radial tensioning force which can be generated by the annular spring can be still further increased without much technical outlay by arranging the annular spring within a cylindrical collar of the stop, against which it becomes braced during the course of its pretensioning.
A further advantage of the construction according to the invention lies in the fact that the radial tensioning forces to be generated by the annular spring are obtained for only a short sliding stroke of the hublike shaft section, without any need to actuate the annular spring itself manually at all. Therefore, in contrast to the known tensioning device, no accessibility of the tensioning device is required for the assembly or for bringing the two shaft sections into mutual engagement. This makes it possible to use the tensioning device according to the invention with particular advantage when the shaft sections are the shaft ends of a final drive shaft and of a final gear drive shaft of a motor vehicle transmission line which are required to be mutually coupled, and the shaft end of the final gear drive shaft and the stop fastened to the final gear and associated with the annular spring protrude into a tube end of a central tube connected by flanges both to the engine gearbox unit and to the final gear of the motor vehicle and housing the final drive shaft.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.